Poly-Armour Has Become The New Standard In Brake Line Replacement Over The Last Several Years. The Difference Being That Poly-Armour Offers 30 Times The Corrosion Resistance Of Galvanized Steel Alone. Requirements For Brake Tubing. Underneath The Pvf-Coating Is A Double-Wall, Low Carbon Steel, Copper Brazed Tubing Which Meets All International And U.